Leibniz s solution to the problem of evil James Franklin Think 5 (Autumn 2003), 97-101 Mark Piper s article `The perennial problem of evil (Think 4) summarises received ideas on the question. They are: It would be a moral disgrace for God (if he existed) to allow the many evils in the world, in the same way it would be for a parent to allow a nursery to be infested with criminals who abused the children. There is a contradiction in asserting all three of the propositions: God is perfectly good; God is perfectly powerful; evil exists (since if God wanted to remove the evils and could, he would). The religious believer has no hope of getting away with excuses that evil is not as bad as it seems, or that it is all a result of free will, and so on. Piper avoids mentioning the best solution so far put forward to the problem of evil. It is Leibniz s theory that God does not create a better world because there isn t one that is, that (contrary to appearances) if one part of the world were improved, the ramifications would result in it being worse elsewhere, and worse overall. It is a bump in the carpet theory: push evil down here, and it pops up over there. Leibniz put it by saying this is the Best of All Possible Worlds. That phrase was a public relations disaster for his theory, suggesting as it does that everything is perfectly fine as it is. He does not mean that, but only that designing worlds is a lot harder than it looks, and determining the amount of evil in the best one is no easy matter. Though humour is hardly appropriate to the subject matter, the point of Leibniz s idea is contained in the old joke, An optimist is someone who thinks this is the best of all possible worlds, and a pessimist thinks
2 the same. And it is in tune with the obvious thought: If God is doing his best, then this must be the best he can do. No-one would maintain that this is a plausible theory, at first glance. Everyone thinks they could do a much better job than the present shambles, given enough power. Let us first note, though, that the barest possibility that Leibniz is right is enough to dispose of the second of the received ideas above, the alleged logical incompatibility of God s goodness, God s perfect power, and the existence of evil. To show propositions are logically compatible, all that is needed is to exhibit a merely possible scenario in which they are all true. In Leibniz s Best of All Possible Worlds scenario, they are all true. Therefore, the three propositions are compatible. To see why we should doubt our initial feeling that it is easy to imagine a better world, we need to remember that perfect power comes with perfect knowledge, in particular, perfect knowledge of how things constrain one another, of how doing this here makes doing that there impossible. There are many examples in the formal sciences, the disciplines like operations research, control theory, statistics and theoretical computer science that have emerged in the last sixty years at the interface between mathematics and engineering. The flavour of these results is easily seen in the first investigation of this kind, Euler's eighteenth-century paper on the bridges of Königsberg. The citizens of Königsberg noticed that it seemed to be impossible to walk across all seven bridges over the River Pregel, without walking across at least one of them twice:
3 Figure 1: The Königsberg bridges Euler proved mathematically that they were right: though it is easy at any point to choose a bridge to walk over, it is absolutely impossible to perform the whole task as a whole. Although God could make bridges, islands or citizens differently, he could not make them the same while at the same time making it possible for the citizens to walk over all the bridges once and once only. That is only one example, of course. There are many such, well appreciated by mathematicians, engineers, planners and architects. Philosophers are possibly the worst people to appreciate them, as most philosophers have never built, let alone designed, so much as a model aeroplane. They therefore find it easy to write, as Piper does, an all-powerful God, by definition, would be able to achieve the end (the greater good) without using the means (the evil). Not so fast. Good and evils can be more intimately and necessarily connected than that. That, indeed, is the real point of the free will defence. It is not remotely plausible that all instances of evil can be explained away as effects of free will misused. It is, however, not easy to see how the good of moral responsibility can be disconnected from the evil of immoral choices. Even if the Best of All Possible Worlds theory has some remote possibility, is it at all plausible? If we looked around the world with unprejudiced eyes, would we not conclude, as Hume suggests, that it was made by an apprentice God as a poor first effort? Why is the religious believer straining so hard to look for excuses for God? The Leibnizian solution is not plausible, in isolation. It is not intended to be. It only makes sense in a certain context, namely, the context of prior good reasons that one may have for
4 believing in God. Perhaps one has found the traditional arguments for the existence of God satisfying. Or some particular religion has seemed a sound candidate for an argument to the best explanation, being a coherent explanation of all facts (including moral ones) superior to alternatives. Or perhaps the logical tension has just become too great between a materialistic view of the world which implies that humans do not matter, and moral statements, which imply they do. That is when it is time to ask if there may be excuses for the evil in God s creation. That is enough of being defensive. The problem of evil has a kick in its tail for the atheist. The atheist who talks about the problem of evil typically uses some very strong moral language. Piper writes of the intensity and sincerity with which one s imagination is used to make as vivid as possible the true horrors that lie behind the all too common word `evil we see beautiful, innocent children reduced to corrupted hulks of suffering That reaction to evil is the right one. But is it compatible with the conclusion the atheist has in store for us, just after the end of his argument? Consider, for example, the materialist world-picture which most atheists believe in. Is there really evil in the materialist world? Of course, there are animals in pain and distress, but one who takes an absolute perspective can well ask, why does that matter? Ordinarily one thinks that the suffering of a human is a tragedy but the explosion of a dead galaxy is just a firework. Materialism, though, denies the distinction between the two, since it takes humans to be the same kind of things as galaxies, namely, moderately complicated heaps of matter. If the fate of a galaxy cannot give rise to a problem of evil, because its fate cannot in any absolute sense matter, then neither can the fate of a brain. In posing the problem of evil, a materialist who does not really believe in positive worth is cynically trading on our sense of the importance of those who suffer, knowing he will undermine it later.
5 The atheist s argument from evil has a moral force behind it. It engages our attention and rightly so by forcing us to remember how terrible evil is. Evil matters because it happens to things of great value at least ourselves and those with whom we share a common humanity that allows us to understand their suffering. If the conclusion of the problem of evil entails a reductio of that notion of value, as well as of the existence of a good God, then it will have undermined itself by proving too much. The atheist who poses the problem is left in the end with the conclusion that evil was really not worth worrying about in the first place. That is bad faith, and what seemed to be the moral force of his position is exposed as a mere self-serving indignation. The materialist view of evil is frivolous. If all there is to evil is that I have a personal dislike of suffering, there is no moral standpoint from which I can criticise God for failing to alleviate it. So the very existence of evil as a matter of absolute seriousness is a substantial reason to believe that the materialist world picture is false. Since the leading alternative theory involves a good and powerful God, that is a reason to believe there must be some solution to the problem of the evil. One last question to the atheist. Perhaps the evil of this world is so bad that there is an obvious possible world that is better, namely the empty one? Consider someone whose suffering is so bad that they wish they had never been born. The atheist should imagine giving to such a person a button which the sufferer can press to render themselves never born. Will the atheist be happy for the sufferer to press the button? Perhaps. But the more relevant thought experiment involves a button that the sufferer can press to render the whole universe never born. Would the atheist still be happy to hand over the button? If the atheist remains entirely contemptuous of the religious appeal to the Best of All Possible Worlds theory, he ought to have no hesitation in handing it over. For hesitation involves weighing the claims of the sufferer against those of others who value their lives weighing them in the way that God does in creating the actual world, according to the Leibnizian.
6 School of Mathematics University of New South Wales http://www.maths.unsw.edu.au/~jim